Conventionally, a power source of power to be consumed is generally supplied only from an electric power company, and enough power is supplied such that it is not necessary to select a supply source.
In other words, it has generally been recognized that the power from such an electric power company can meet the power demand for all consumers, and is sufficient enough that there are rarely any power outages.
However, in recent years, due to earthquakes and other accidents, the dangers of relying on only a single power source (for example, a commercial power supply that is supplied by an electric power company) have become apparent.
Accordingly, the use of natural energy such as solar photovoltaic generation has been spreading, but there are many obstacles to using natural energy such as solar photovoltaic generation. For example, in the case of solar photovoltaic generation, a power conditioner (direct current/alternating current converter) is generally used, and if there is an outage in the commercial power source, the operation of such a power conditioner may be stopped considering the safety thereof even if the power generation capacity is sufficient. In order to utilize solar photovoltaic generation during an outage of the commercial power source, for example, consumers must manually set the power conditioner to an autonomous operation mode, but this may be extremely difficult during a disaster.
Further, even during periods of normal supply of the commercial power source, in the case of selling power, if many solar photovoltaic generation facilities are installed, particularly in adjacent regions, the main line voltage may rise. This can cause restrictions to act on the operation of the power conditioner, which has frequently led to cases in which power cannot be sufficiently sold.
Moreover, in addition to power generation by natural energy such as solar power, wind power, and water power, many other power options are becoming available such as fuel cells, co-generation power generation, and utilization of midnight power by batteries. However, there are many conditions on such options, including the costs of such power generation, the utilization of heat generated together with such power, increases in power generation for utilization as a heat source, restrictions on the time period in which such power can be utilized, and the like, and thus technology for satisfying these conditions to effectively utilize such options is needed.
Patent Document 1: JP H11-113188 A